Direct dental restorative materials consist of a curable phase, typically a methacrylate resin, an initiator and a filler system. These materials are typically highly filled with particulate such as nanoscale particles, micrometer milled materials and/or solution grown inorganics. Furthermore, similar compositions made from pre-cured “composites” (e.g., dental mill blanks) have been introduced to the market, where the material is cured out of the mouth and shaped into a final restorative shape (e.g., inlay, onlay or crown) via a reduction process (e.g., milling). All of these dental restorative materials have requirements that include high strength, stiffness, and fracture toughness to function in the oral environment. Especially in large posterior restorations, a higher fracture toughness material is highly desirable.
Attempts have been made to include fibers in dental restorative materials in order to improve their mechanical properties. However, this has come at a cost to handling and aesthetic characteristics. The use of fibers unfortunately creates a stiff, “crunchy” type of handling that is difficult to work with (e.g., shape, and feather). Once cured, the surfaces of these dental restorative materials rapidly lose their gloss with every day wear. Additionally, many of these dental restorative materials produce a highly opaque material due to refractive index mismatch between the fiber and the resin. This refractive index mismatch results in a less than desirable aesthetic result.
As such, there is a need in the art for a composite material that includes fibers, where the composite material is easy to handle and provides good aesthetics properties while still providing the necessary mechanical properties for use as a dental restorative material.